Ch. 1 - A Review of General ChemistryWorksheetSee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

Drawing Lewis Structures is something we learned how to do in Gen Chem. Nothing has changed since then, but now since we know about bonding preferences, that makes it a lot easier. 

Lewis Structure Rules

Concept #1: How to use Organic Chemistry to make Lewis Structures easier. 

*You might have learned a slightly different version, but this is close enough, you get the point.

Example #1: Drawing the Lewis Structure for N2H4.

In this example, we were left with a separation of charges (+ next to -), so we rearranged the σ-framework to see if we could remove them.

  • This is a process of trial and error. Don’t be afraid to draw the wrong structure at first!

Practice: Draw the Lewis structure of the molecule

Practice: Draw the Lewis structure of the molecule

Practice: Draw the Lewis structure of the molecule

Like the new method? Prefer the old one instead? Feel free to use whichever method you like more. As long as you get the right answer on the exam, that’s all I care about.

Additional Problems
Which is an acceptable Lewis structure of CO (where formal charges are not shown)?
What is the total number of electron groups surrounding the central carbon atom in the correct Lewis structure for CHF3? A. 2 B. 3 C. 4
Identify the lowest-energy Lewis structure for nitrogen oxide. (Formal charges not shown.)
Which is an acceptable Lewis structure for diazomethane?
Draw a Lewis dot structure for each of the following compounds:  (a) CH3CH2OH 
Draw a Lewis dot structure for each of the following compounds:  (b) CH3CN 
Draw a Lewis structure for the following species. Include all nonbonding pairs of electrons and any formal charges. CH3NO2
Draw a Lewis structure of the anion AlBr4- and determine its geometry. 
Construct a Lewis structure for NO 2F. Include all nonbonding electrons and formal charges.
Write a Lewis structure for each of the following: (a) SOCl2
Write a Lewis structure for each of the following: (b) POCl3
Draw the Lewis structure of acetaldehyde, CH 3COH, clearly indicating all bonding and non-bonding pairs of electrons. 
Write a Lewis structure for each of the following: (c) PCl5
Write a Lewis structure for each of the following: (d) HONO2 (HNO3)
Add any unshared electrons to give each element an octet in its valence shell in the formulas below and indicate any formal charges. Note that all of the hydrogen atoms that are attached to heteroatoms have been drawn if they are present.
Draw the structure of BH 3-THF. 
The connectivity of carbon oxysulfide is OCS. (a) Write a Lewis structure for carbon oxysulfide that satisfies the octet rule. 
Write a Lewis structure for each of the following organic molecules:  (a) C2H3Cl [vinyl chloride: starting material for the preparation of poly(vinyl chloride), or PVC, plastics]
What is the  total number of electron groups  surrounding each nitrogen atom in the correct Lewis structure for N2F2?  A. 2 B. 3 C. 4 D. 5 E. 6
Write a Lewis structure for each of the following organic molecules:  (b) C2HBrClF3 (halothane: a non flammable inhalation anesthetic; all three fluorines are bonded to the same carbon)   
Write a Lewis structure for each of the following organic molecules: (c) C2Cl2F4 (Freon 114: formerly used as a refrigerant and as an aerosol propellant; each carbon bears one chlorine) 
Construct ONE (1) Lewis structure for the formula C2H7ON. Include all lone pairs and formal charges . 
Construct a Lewis structure for H2O2. Include all nonbonding electrons and formal charges. As a bonus, show the correct structural formula. 
Draw all carbon atoms, hydrogen atoms, and lone pairs for the following compound:
Dimethylformamide (DMF), HCON(CH3)2, is an example of a polar aprotic solvent, aprotic meaning it has no hydrogen atoms attached to highly electronegative atoms. (a) Draw its dash-type structural formula, showing unshared electron pairs.
Draw all carbon atoms, hydrogen atoms, and lone pairs for the following compound:
Draw all carbon atoms, hydrogen atoms, and lone pairs for the following compound:
Each of the following species will be encountered at some point in this text. They all have the same number of electrons binding the same number of atoms and the same arrangement of bonds; they are isoelectronic. Specify which atoms, if any, bear a formal charge in the Lewis structure given and the net charge for each species. (a) :N≡N:
How many electrons in the correct Lewis structure of   Cl3CCCH are  NOT  shared in covalent bonds?a. 18b. 20c. 22d. 24e. 26
Draw the Lewis structure for: 
Show the Lewis structure for  N2O4  (clearly indicate charges if necessary): 
Why is the following Lewis structure unlikely to contribute much to the bonding in NCO? Choose all the answers that apply. a. Carbon has a positive formal charge. b. Carbon is not a good central atom. c. Oxygen should have the negative charge. d. Carbon has a + 1 formal charge and O has a -1 formal charge. e. Nitrogen has a - 2 formal charge and oxygen has a + 2 formal charge. 
Which of the following Lewis structures is incorrect? 
Choose the answer that best describes the lone pairs on the molecule below. a. There are 2 lone pairs of fluorine, 3 lone pairs on oxygen, and 2 lone pairs on nitrogen. b. There are 3 lone pairs of fluorine, 2 lone pairs on oxygen, and 1 lone pair on nitrogen. c. There are 3 lone pairs of fluorine, 2 lone pairs on oxygen, and 2 lone pairs on nitrogen. d. There are 3 lone pairs of fluorine, 3 lone pairs on oxygen, and 1 lone pair on nitrogen. 
Which of the following has a total of five lone pairs of electrons?
Be sure to answer all parts.Draw the Lewis structure for the given organic molecules. Be sure to include any lone pairs. (a) ethanol (CH3CH2OH) (b) methylamine (CH3NH2) which is used in tanning 
How many lone pairs of electrons are on the indicated oxygen atom?a. fourb. threec. noned. twod. one 
Draw a Lewis structure for C2H3CI. Show all unshared electron pairs. None of the atoms bears a formal charge, and all atoms have octets (except for hydrogen atoms, which have duels).